JPS6133146A - 2,6-dimethylphenyl p-halogenobenzoate and preparation thereof - Google Patents

Abstract

NEW MATERIAL:A 2,6-dimethyl p-halogenobenzoate expressed by formula I (X is halogen). EXAMPLE:2,6-Dimethylphenyl p-chlorobenzoate. USE:A precursor substance for 4-(halogenobenzoyl)-2,6-dimethylphenols which are monomers for heat-resistant polymers. PREPARATION:For example, a p-halogenobenzoyl halide expressed by formula II (X and Y are halogen) is reacted with a 2,6-dimethylphenol or an alkali metal salt thereof expressed by formula III (M is H or alkali metal) in a solvent, preferably 2,6-dimethylphenol at 0-350 deg.C for 1min-50hr, and the excessive 2,6- dimethylphenol is distilled under reduced pressure after the reaction to afford the aimed compound expressed by formula I.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a novel compound useful as a precursor of 4-(parahalogenbenzoyl)-2,6-dimethylphenol, which is a monomer for heat-resistant polymers. The present invention relates to a parahalogenated benzoic acid 2,6-dimethylphenyl ester and a method for producing the same.

(Prior Art) Parahalogenated benzoic acid phenyl esters having no substituent at the 2.6-position are known. For example, phenyl parafluorobenzoate is a crystal with a melting point of 65C (Pharmaceutical Journal Vol. 78, p. 546).

(1958), phenyl parachlorobenzoate.

and phenyl parabromobenzoate each have a melting point of 100
(I)ictiona which is a crystal of C and 117C
ryof Organic (: compounds 2nd
Volume, page 602.

and Volume 1, Page 421, □xford un
iversitypress, 1965).

(Means for achieving the objective) 2. Parahalogenated benzoic acid 2 having a substituent at the 6-position
．． 6-dimethylphenyl ester has been completely unknown until now, but the present invention aims to provide such a novel compound and a method for producing the same.
be.

(In the formula, X represents a halogen atom.) This is bacyhalogenated benzoic acid 2,6-dimethylphenyl ester.

Further, the present invention provides a parahalogenated benzoic acid represented by the formula (n) (wherein, X and Y represent a halogen atom, and each of X and Y may be the same or different). halide and 2.6
- Parahalogenated benzoin 112 characterized by reacting with dimethylphenol or its alkali metal salt
A method for producing 2.6-dimethylphenyl ester,
Furthermore, one aspect of the present invention is that parahalogenated benzoic acid and 2,6-
This is a method for producing parahalogenated benzoic $2.6-dimethylphenyl ester, which is characterized by esterifying parahalogenated benzoin with dimethylphenol.

Parahalogenated benzoic acid 2, which is a novel compound of the present invention,
6-dimethylphenyl ester may be produced by any method, but one preferred production method is to use parahalogenated benzoic acid halide represented by formula (n), and 2. A method of reacting 6-dimethylphenol or an alkali metal salt thereof, the reaction formula of which is expressed as follows (in the formula, M represents a hydrogen atom or an alkali metal atom, and X and Y are as described above). ) This reaction can be carried out without a solvent, but of course it is also preferable to use a solvent that does not adversely affect the reaction. Such solvents include: halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane; aromatic hydrocarbons such as benzene, toluene, xylene, and tetralin; ethyl acetate, propionic acid; Esters such as ethyl: Halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, and chlornaphthalene: Nitro compounds such as nitrobenzene, nitrotoluene, and nitromethane: N,N-dimethylformamide, N,N- Amides such as dimethylacetamide, tetramethylurea, N-methylpyrrolidone, and hexamethylphosphoramide Sulfur-containing compounds such as dimethylsulfone, dimethylsulfoxide, and sulfolane; Ethers such as diethyl ether, dihydrofuran, and dioxane: 2 Examples include 6-dimethylphenol itself.

Further, although this reaction proceeds without using a catalyst, it is also possible to use a suitable catalyst. Particularly when 2,6-dimethylphenol is used as a reagent, hydrogen halide is generated, so it is also preferable to coexist with a basic substance in order to neutralize this. Such basic substances include tertiary amines JII such as triethylamine, pyridine, and quinoline; cyclic amidines such as *6-diazabicycloundecene-7; N,N-dimethylformamide, N,N-dimethylacetamide , tetramethylurea, N-methylpyrrolidone, and other aprotic amides; carbonates and hydrogencarbonates of alkali metals or alkaline earth metals such as lithium carbonate, sodium hydrogen carbonate, potassium carbonate, and calcium carbonate.

The temperature and reaction time for this reaction vary depending on other conditions such as the solvent used and the presence or absence and type of catalyst, but
It is usually in the range of 0 to 35Qc and 1 minute to 50 hours, preferably in the range of 30 to 250C and 5 minutes to 20 hours.

The halogenated benzoic acid halide used in this reaction may be produced by any method.

Another preferred method for producing the compounds of the invention is
This is a method of dehydrating and esterifying halogenated benzoic acid and 2,6-dimethylphenol, and the reaction formula is expressed as follows.

(In the formula, X is as described above.) In the case of this dehydration esterification reaction, it is preferable to use an acid catalyst. Such acid catalysts include boric acid, sulfuric acid,
Mineral acids such as phosphoric acid, polyphosphoric acid, hydrochloric acid, and hydrogen heptafluoride Heteropolyacids such as nidodecamolybdophosphoric acid, dodecamolybdosilicic acid, dodecatungstophosphoric acid, and dodecatungstosilicic acid: chlorosulfonic acid, bromsulfonic acid fx
Halogenated sulfonic acids: methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid fX Organic sulfonic acids/acids: boron halide, aluminum halide, silicon halide, titanium halide, tin halide , zirconium halides, antimony halides, bismuth halides, iron halides, nickel halides, halogenated steel,
Lewis acids such as zinc halides; inorganic cation exchangers such as zirconium phosphate and various zeolites; organic cation exchangers having sulfonic acid groups or Fi/ and fluoroalkylsulfonic acid groups are used.

Further, although this dehydration esterification reaction can be carried out without a solvent, it is also a preferable method to use a solvent that does not adversely affect the reaction. Such solvents include
Aliphatic hydrocarbons such as hexane, heptane, and octane; Aromatic hydrocarbons such as benzene, toluene, xylene, and tetralin; Carbon halides such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane. Hydrogens: halogenated aromatic hydrocarbons such as chlorobenzene, dicumylbenzene, brombenzene, kuhnaphthalene, etc.; Nido compounds such as nitrobenzene and nitrotoluenate; sulfur-containing compounds such as dimethylsulfone, dimethylsulfoxide, and sulfolane; ; Ethers such as tetrahydro-7rane and dioxane are used.

Further, in this dehydration esterification reaction, it is also a preferable method to carry out the reaction while removing generated water from the reaction system. Therefore, for K, a method is adopted in which a reaction is carried out at a temperature higher than the boiling point of water, an inert gas is introduced as an entrainer, or a substance that is azeotropic with water is introduced. Of course, it is also a preferred method when the solvent also serves as an azeotropic agent.

The temperature and reaction time for this dehydration esterification reaction are as follows:
Although it varies depending on the presence or absence of a solvent and catalyst used and the type of food, the temperature is usually 30 to 350 C and 1 minute to 50 hours, preferably 50 to 300 c% and 5 minutes to 20 hours.

(Effect of the invention) The parahalogenated benzoic acid 2,6-dimethylfer ester of the present invention is a monomer for heat-resistant polymers.
-(halhalogenobenzoyl)-2,6-dimethylphenol is useful as a precursor. As monomers for such heat-resistant polymers, monomers in which all functional groups are bonded to the para position are particularly important. The compounds of the present invention and parahalogenated benzoic acid phenyls having no substituent at the 2.6-position undergo a 7-liss rearrangement reaction in the presence of a Lewis acid such as aluminum chloride to produce parahalogenobenzoylphenols. can be easily converted into

However, in the case of parahalogenated phenyl benzoate that has no substituents at the 2,6-positions, in addition to 4-(゛parahalogenobenzoyl)phenol, in which a parahalogenobenzoyl group and a hydroxyl group are bonded to the para position, Bound 2-(parahalogenobenzoyl)phenol is always produced as a by-product. It is often difficult to separate and purify this orthoform.

On the other hand, in the compound of the present invention, the two ortho positions of the hydroxyl group of the phenol compound to be generated have already been substituted with methyl groups, so even if the Fries rearrangement reaction is performed, no ortho form is produced at all, and the para form is formed. This is very convenient because only 4-(parahalogenobenzoyl)-2,6-dimethylphenol is obtained.

(Examples) Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 87.5 f (0.5 mol) of parachlorobenzoic acid chloride, 91.5 t (0.7 mol) of 2,6-dimethylphenol
5 mol) was placed in a flask equipped with a nitrogen inlet, a stirrer, and a cooling tube, and reacted with stirring at 140 to 150 C for 9 hours while bubbling dry nitrogen. After the reaction, excess 2,6-dimethylphenol was distilled off under reduced pressure, and a colorless transparent liquid 1231 was obtained with a boiling point of 136 to 138C/5IIIHg.

This compound has an infrared absorption spectrum (1
735cIn-': engineering, ;<C=O of chill bond), proton-NMR shown in FIG. 2 (δ8.131P.

2H, double: δ7.45 ppm,
2H, double: δ7.03 ppm, 5
H, singlet: δ2.13m, 6H.

singlet ), and mass spectrum #(m/, e
=■260:P), it was identified as parachlorobenzoic acid 2,6-dimethylphenyl ester.

The yield was 94% based on the parachlorobenzoic acid chloride used.

Example 2 Parafluorobenzoic acid chloride 15.99 (0.1%
), 2,6-dimethylphenol 14.7 t (0
, 12 mol) in the same manner as in Example 1. After the reaction, excess 2.6-dimethylphenol was distilled off, and 25.59% of a colorless and transparent liquid was obtained which distilled out at 132 to 154 c/3#llHg.

This liquid has an infrared absorption spectrum (17
35 (+jIL@: c=o of ester bond), proton-NMR shown in Figure 4 (δ8.21 ppm, 2H
.

doublet - doublet; δ7,13 p
pm, 2H, doublet.

-double; δ7. o 3 p-, 5H, si
nglet; δ2.13 IP, 6 H, sing
It was identified as parafluorobenzoic acid 2,6-dimethylphenyl ester from the mass spectrum (m/e=244:P). The yield was 96% based on the parafluorobenzoic acid chloride used.

Example 3 A reaction was carried out in the same manner as in Example 1 using 22 t (0.1 mol) of parabromobenzoic acid chloride and 14.79 (0.12 mol) of 2,6-dimethylphenol.

After the reaction, excess 2.6-dimethylphenol was distilled off to obtain a colorless and transparent liquid 299 distilled at 135-136 U/2.5 111Hg. This liquid is the fifth
Infrared absorption spectrum shown in the figure (1755Qe-1: C=O of ester bond), proton-NMR shown in Figure 6
(δ8.06 ppm, 21H, double
; δ7.60°2 H, double; δ7.03
ppm, 3H, singlet; δ2.13 p
It was identified as parabromobenzoic acid 2,6-dimethylphenyl ester from the Hm, 6H, singlet) and mass spectra (m/e=305:P). The yield was 95% based on the parabromobenzoic acid chloride used.

Example 4 Parachlorobenzoic acid 15.79 (0.1 mol), 2.
Put 14.7 f (0.12 mol) of 6-dimethylphenol and 30 f of polyphosphoric acid into a flask, add 100 to 1
The reaction was carried out at 10C for 24 hours with stirring. After the reaction, the mixture was cooled to room temperature and water was added. Then, it was extracted with ethyl acetate. The ethyl acetate solution was washed with an aqueous sodium bicarbonate solution to remove unreacted parachlorobenzoic acid. After drying this ethyl acetate solution over anhydrous chloride, ethyl acetate and excess 2,6-dimethylphenol were distilled off. Then, by distillation under reduced pressure, 16
A colorless transparent liquid 211 was obtained which was distilled at 6 to 138C/311+1Hg.

This liquid was parachlorobenzoic acid 2 obtained in Example 1.
, 6-dimethylphenyl ester and showed exactly the same infrared absorption spectrum and proton NMR spectrum.

The yield is 91% based on the reacted parachlorobenzoic acid.
%Met.

Reference Example Parachlorobenzoic acid 2,6-dimethylphenyl ester of the present invention (0.25 mol), m water [aluminum oxide (0
, 27 mol) in dry orthodichlorobenzene and reacted at 150 °C with stirring for 4 hours to carry out a 7liss rearrangement reaction, resulting in 4-(parachlorobenzoyl) -2,6- Dimethylphenol was obtained with a yield of 95%.

A similar reaction was carried out with parachlorobenzoic acid phenyl ester (0
, 25 mol), 2-(parachlorobenzoyl)phenol (13%) was produced in addition to 4-(parachlorobenzoyl)phenol (80%).

[Brief explanation of drawings]

Figure 1 shows the infrared absorption spectrum of the compound obtained in Example 1, Figure 2 shows the same proton-NMR, and Figure 3 shows Example 2.
Figure 4 shows the infrared absorption spectrum of the compound obtained in Example 3, Figure 4 shows the same proton-NMR, Figure 5 shows the infrared absorption spectrum of the compound obtained in Example 3, and Figure 6 shows the same proton-NMR.
shows.

Claims (3)

[Claims] (1) Parahalogenated benzoic acid 2,6-dimethylphenyl ester represented by the formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, X represents a halogen atom.) (2) Formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, X and Y represent halogen atoms, and X and Y may be the same or different. ) and a parahalogenated benzoic acid halide represented by 2,6
- parahalogenated benzoic acid 2, characterized by reacting with dimethylphenol or an alkali metal salt thereof;
Method for producing 6-dimethylphenyl ester. (3) A method for producing parahalogenated benzoic acid 2,6-dimethylphenyl ester, which comprises esterifying parahalogenated benzoic acid and 2,6-dimethylphenol.